Presence information may be published to a presence server. Entity tag values identify the data associated with a data session. The presence server includes data session slots that store data associated with a data session's operating state. Conventionally, publication messages related to the data session slot included an old entity tag value in the request and the new operating state. The presence server replaced the stored operating state with the new operating state and returned a new entity tag value associated with the new operating state. The new entity tag value was then used in the next publication message. Therefore, the entity tag value traditionally changed with every new publication of the operating state. An authentication, authorization, and accounting (AAA) server updated the stored entity tag value with each transaction. Therefore, the AAA server kept an entity tag value to identify the data content. If the AAA server was implemented as a redundant cluster, the entity tag value was stored in a persistent storage or communicated across all nodes in a cluster. Storing the entity tag value and/or communicating the entity tag value across all nodes in the cluster is an expensive task.
If the entity tag value identifying the data content in the data session slot was lost, new data session slots were allocated, which also caused the sequence of operating states to be lost. Allocating additional data session slots required additional storage capacity and composition logic in the presence server to compare the operating states in the different slots and determine what information to report to applications that subscribed to the operating state of the mobile unit. An increased workload consequently occurred on the presence server.